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Home My WebLink About14- Task Order 6-27-14 Tetra Tech, Inc. Bozeman Landfill Resampling Wells, Additional Drilling Time and Mitigation Activities Task Order June 2014 Task Order for Resampling Wells, Additional Drilling Time and Additional Mitigation Activities Bozeman Landfill Bozeman, Montana June 27, 2014 CLIENT: CONSULTANT: The City of Bozeman Tetra Tech, Inc. P.O. Box 1230 851 Bridger Drive, Ste 6 Bozeman, Montana 59711-1230 Bozeman, MT 59715 Attention: Mr. Rick Hixson. PE Attention: Mr. Kirk A. Miller INTRODUCTION This Task Order outlines additional activities requested by the City after the date of our last Modification, which was submitted on April 4, 2014. These tasks are relative to the vapor intrusion investigation and mitigation work at the Bozeman Landfill site. The scope of work expanded for several tasks, including drilling and sampling the new monitoring wells and installation of a new mitigation system and changes to existing mitigation systems. Since this work relates to tasks conducted under our original landfill gas investigation project (job number 1140560303A), rather than the new landfill remediation contract (job number 114-560442), we have submitted this under the previous contract. SCOPE OF WORK This Modification is for the following work, which is outside the scope of our previously approved Task Orders: Resampling of New Monitoring Wells The ten new wells installed under the Groundwater Program were sampled in March 2014 and concentrations of volatile organic compounds above Montana's Groundwater Protection Standards were reported in an offsite well and several onsite wells. We recommended and the City concurred that they be resampled. Thirteen samples were collected and submitted for laboratory analysis. This task includes hours for data validation time, map preparation and data management. Longer Drilling Time During drilling of the ten groundwater-monitoring wells using a hollow stem auger drill rig, we encountered dense silts and gravels in several borings and a period of warm weather, which created soft soils and precluded drill rig access to several locations. When the driller's returned several weeks later we requested they bring an air rotary drill rig to ensure we could reach the target depths for wells MW-24 and MW-26. This did not affect the driller's costs because we had them bill by the foot, however, it did take a longer time to drill the wells, thereby increasing our labor hours for field oversight. Task Order—June 2014 Modification Bozeman Landfill, Bozeman, Montana June 27, 2014 Mitigation System Changes Several homeowners have requested changes to their mitigation system discharge that are within the range of typical system installations. The McGovern's requested their fan be surrounded by a box with insulation since it sits beneath their deck. The Moriarity's requested their two discharge pipes be carried through a second roof line to get above eaves where frost build up occurred during cold periods last winter and there have been several smaller adjustments. We anticipate there will be more requests as the summer progresses and homeowners spend more time in their yards or with windows open. • The Olsen's returned to their home after a winter spent out of state and requested a mitigation system for their home, so a system was installed. The first post mitigation indoor air sampling of this home will be conducted. • We are conducting quarterly inspections of the mitigation systems to ensure the system is running and to check on vacuum levels in the discharge pipe and subslab vacuum measuring points. We have determined that our original labor estimate for the inspections was optimistic. We spent almost 20 man hours just tracking down homeowners to set appointments, rescheduling appointments and waiting for no shows. In addition, the actual data collection effort took longer than anticipated due to sociable homeowners and several more events will occur this summer. • At the last update meeting it was decided to add visual vacuum gauges (i.e., manometers) on the mitigation system discharge pipes. After reviewing field notes, we determined that manometers were installed in many of the systems during construction (we added this feature part way through the program). Placing visible manometers is a challenge in some homes because they do not have an easily accessible discharge pipe or the piping is in a crawl space. We will revisit these homes to see if a practical location can be found for a manometer. We estimate that approximately eight homes that do not currently have manometers could be modified to provide a reasonably accessible manometer. • We are updating our mitigation system records by taking photographs of key aspects of each system that are visible. This will allow team members to better understand each installation without having to travel to the site or disturb homeowners. We are requesting homeowner permission prior to taking photographs. Special Conditions Execution of this Task Order constitutes acceptance of all terms and conditions contained in Tetra Tech's Professional Services Agreement with the City of Bozeman, dated January 3, 1994 and Amendment Nos. 1, 2, 3, and 4 of the Professional Services Agreement dated July 31, 1995; January 1, 1996; March 17, 1997; and December 10, 2001, respectively. CLIENT: CONSULTANT: City of Bozeman Tetra Tech l By: C /1�/�/'� By: a \k} Its: C ,Ty avid, ct P( Its: Sr. Proiect Manager 11 Date: . C D 1 1 Date: June 27. 2014 Page 2 of 2 ESTIMATED BUDGET JUNE 2014 MODIFICATION TO CONTRACT FOR RESAMPLING,DRILLING TIME AND CHANGES TO MITIGATION SYSTEMS BOZEMAN LANDFILL BOZEMAN,MONTANA Date Submitted:June 27,2014 Resamole of New Groundwater Monitorina Wells Field Work Units Rate Cost Project Manager/Senior Hydrogeologist,per hour 4 $170 00 $680 00 Hydrogeologist,per hour(sampling and data analysis) 36 $95 00 $3,420 00 Data validation/management,per hour 6 $95 00 $570 00 CAD,per hour 4 $75 00 $300 00 Staff Field Personnel,per hour 16 $65 00 $1,040 00 Labor Subtotal $6,010.00 DIRECT COSTS Tetra Tech Vehicle Mileage,per mile 10 $0.60 $6 00 Water Level Meter,per day 2 $25 00 $50.00 YSI Multi-Meter,per week 2 $100.00 $200 00 Sampling Disposables-Filter,each 10 $18 00 $180 00 Sampling Disposables-Bailer,each $4 75 $0 00 Sampling Disposables-Low-flow tip,each 10 $2 50 $25 00 Sampling Disposables-pump tubing,per foot 350 $0 25 $87 50 Sampling Disposables -Miscellaneous,each 10 $3 00 $30 00 Miscellaneous Shipping,estimate 1 $100 00 $100 00 Lab Sample Shipping(overnight to lab),estimate 1 $150.00 $150 00 Lab Analysis(VOCs,Method 8260 Low Level),each 13 $95.00 $1,235 00 Tetra Tech 10%markup on Subcontractors,Equipment,and Materials $206 35 Direct Costs Subtotal $2,263 85 Resample of New Groundwater Monitoring Wells Total $8,273.85 Longer Drilling Time Project Manager/Senior Hydrogeologist,per hour 1 $170 00 $170.00 Assistant Project Manager/Hydrogeologist,per hour 16 $95 00 $1,520.00 Labor Subtotal $1,690 00 DIRECT COSTS Vehicle,mileage 5 $0 60 $3.00 Per Diem and Lodging,per person per day $140 00 $0 00 Direct Costs Subtotal $3,00 Longer Drilling Time Total $1,693.00 Changes to Mitigation Systems.Inspections and Manometers Project Manager/Senior Hydrogeologist,per hour 16 $150 00 $2,400 00 Assistant Project Manager/Hydrogeologist,per hour 60 $95 00 $5,700 00 Project Scientist,per hour(post mitigation sampling and manometer install) 40 $65 00 $2,600 00 Data validation,per hour 4 $95 00 $380 00 Field Technician,per hour(inspections,photos and homeowner scheduling) 60 $65 00 $3,900 00 Administrative Personnel,per hour 12 $55.00 $660 00 Labor Subtotal $15,640 00 DIRECT COSTS Triple R Mitigation(Olsen's new system and modifications to others) 1 $9,500.00 $9,500 00 Eurofins Air Toxics Lab(Olsen home air sampling costs) 3 $800 00 $2,400 00 Manometers 8 $25 00 $200 00 Direct Costs Subtotal $12,100.00 Additional Mitigation etc.Total $27,740.00 TOTAL OF ALL TASKS $37,706.85 Tetra Tech